I'm just going to keep saying this-
I dislike the Grenadier reinforcement change because it homogenizes the factions. Their higher cost is unique.
Instead, I'd recommend improving their cost-effectiveness by increasing their firepower. It has the added benefit of scaling control. You could increase rifle DPS for early game, or MG DPS for late.
Increasing damage or durability would be the actual definition of "power creep" assuming it exists.
That change just very slightly increases cost effectiveness.
After losing 14 gren models you'll be able to get 15th "free" compared to current balance.
Hardly impactful.
Certainly not anywhere near con 7th man cost decrease(cons die like flies so it stacks up fast) or tommies got in the past due to single sniper meaning GG to their manpower.